1. Field of the Invention
The present invention relates generally to the field of exercise equipment. More particularly, the invention relates to an exercise device having what is commonly known as a Smith bar, wherein exercise resistance is provided by a selectable weight stack, rather than free weights.
2. Background
Exercise equipment having a cable and pulley system for lifting a stack of weights has been in use for well over a century. Such equipment comes in a wide variety of designs for performing various exercises. Some have adjustable pulley locations where a handle is attached to a cable for pulling without a defined path of movement. Equipment of this type is often referred to as a functional trainer. One type of such exercise equipment, exemplified, for example, in U.S. Pat. No. 4,402,504, is particularly suited for upper body exercises. This apparatus has an elongated upstanding frame and a carriage that is movable up and down along vertical posts of the frame. The carriage includes one or more pulleys around which a cable is reeved. The cable is further reeved around upper and/or lower pulleys on the frame and is coupled to a source of exercise resistance, such as a plurality of stacked weights. The cable exits the pulley on the carriage and is connected to a handle or similar pulling device. The height of the handle is readily adjustable by moving the carriage on the vertical posts and locking it into position at the selected height. This permits a wide variety of exercises to be performed for exercising muscle groups of the arms and upper body. The amount of exercise resistance is adjusted by selecting more or fewer stacked weights. The range of available exercise resistance is thus determined by the quantity of available weights.
Another type of exercise apparatus is often referred to as a Smith machine. This device consists of a barbell that is fixed within a pair steel rails, which limit the barbell to only vertical movement. Behind each vertical rail is a series of slots or holes on which the barbell can be hooked. This means that the barbell can be secured at any point, unlike an ordinary barbell that must be re-racked after a set of repetitions. This makes a Smith machine safer for those who lift without a spotter, as one only needs to twist the wrist in order to lock the barbell in place in the event that the weight becomes too great. Most Smith machines also incorporate blocks, pegs, or other devices that can be adjusted to automatically stop the barbell at a predetermined minimum height. Unlike a free-weight barbell, the bar on a Smith machine does not move forward, backward or sideways to any appreciable extent. Because lifting on a Smith machine requires less stabilization by the lifter, lifters can usually lift more weight with a Smith machine than with a free-weight barbell. Conventional Smith machines still utilize free weights loaded onto the bar as the source of exercise resistance. Free weights are not only cumbersome to move and store, but also present severe safety hazards.
It would be desirable to include a Smith bar as part of a multi-purpose functional trainer and to utilize a selectable weight stack for exercise resistance with the Smith bar rather than free weights.